I believe that many have and do learn from deconversion stories, but that also creates an even larger problem.
Looking and listening to stories from folk that have left Christianity (limiting myself to just that for now) I tend to hear the same theme time after time.
"I could no longer believe what they were telling me."
The problem is that so many of the basic, very strongly held beliefs of many Christian sects simply do not stand up to examination. If they try to claim that the Bible is "The Word of GOD" then if someone actually does read it, they quickly find out that either God was pretty inconsistent, constantly changing his mind or just plain making stuff up.
If the person actually studies biology, genetics, geology, history, physics, astronomy, archeology or almost any other science area, they pretty soon find that the record that is the universe we live in directly contradicts what they were taught to believe.
The major response from much of Christianity where deconversion is an issue has been "Avoidance".
If they can keep the kids from learning anything beyond the dogma, why then the problem is solved. They create avoidance schools, avoidance colleges, home school programs, set up radio stations and TV networks that just preach the dogma, search engines that filter out opposing views, restrict access to other knowledge and most recently, try to redefine even the terms people use to discuss science, history or any other threatening area.
It is a tactic of desperation, an admission that they have failed, that the battle to retain their dogma has already been lost and that their beliefs are doomed to fall into the trash heap of all the other failed religions.
Anyone so limited that they can only spell a word one way is severely handicapped!